[ovirt-users] Mixing compute and storage without (initial) HCI

Some documentation, especially on older RHEV versions seems to indicate that Gluster storage roles and compute server roles in an oVirt cluster or actually exclusive. Yet HCI is all about doing both, which is slightly confusing when you try to overcome HCI issues simply by running the management engine in a "side car", in my case simply a KVM VM running on a host that's not part of the HCI (attempted) cluster. So the HCI wizard failed to deploy the management VM, but left me with a working Gluster. I then went ahead and used a fresh CentOS 7.7 VM to install the hosted engine the the script variant without an appliance. That went ... not too bad initially, it even found the Gluster bricks eventually, installed the three hosts, looked almost ready to go, but something must be wrong with the "ovirtmgmt" network. It looks alright in the network configuration, where it has all roles, but when I try to create a VM, I cannot select it as the standard network for the VM. Any new network I might try to define, won't work either. So apart from these detail problems: Is the prohibition against mising both roles, gluster and (compute) cluster still in place? Because there are also documentation remnants which seem to indicate that a management engine for an existing cluster can actually be converted into a VM managed by the hosted engine e.g. as part of a recovery, repeating later what the HCI setup attempts to automate.